In some applications using heavy duty cylinders, corrosion resistance and a high level of seal integrity are demanded, either to protect against fluid leaks to the environment in the food industry, for example, or from the environment contaminating the fluid in the cylinder in the offshore hydrocarbon production industry, for example. Another concern in the food industry is the ability to easily clean the exterior of the cylinders.
Traditional steel cylinders that use tie rods provide collection points for contaminants and, the steel material of such cylinders is subject to severe corrosion. Stainless steel offers high corrosion resistance, but the tie rods still provide collection points for contaminants. Welding the cylinder parts would eliminate the need for tie rods, but welding negatively impacts the corrosion resistance of the stainless steel and repair.
Lobed, extruded aluminum bodies are currently used in low pressure (approximately 250 psi or less) pneumatic applications. Stainless steel tie rod type cylinders, both hydraulic and pneumatic are also known, but suffer from the aforesaid drawbacks.